Is the black man tanned? Why are their palms whiter?

It's definitely not tanning, it's genetic.

Have you started studying biology? If you have studied biology, you will know that skin color is determined by genes, just as our skin color is always yellow.

People who immigrate to Africa still give birth to yellow children;

Africans in America haven't turned white, have they?

Why is the palm white? Because the skin of the palm does not contain pigment cells, it is the stratum corneum.